Mitsubishi Montero (2004+). Manual - part 1049

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-39

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CIRCUIT OPERATION

• The M-ASTC-ECU has two power supply lines. 

The M-ASTC-ECU power is supplied to the 
M-ASTC-ECU (terminal 63) from the ignition 
switch (IG2) through the multi-purpose fuse num-
ber 5 in the junction block and through the joint 
connector number 4. The other M-ASTC-ECU 
power is supplied to the M-ASTC-ECU (terminal 
9) from the ignition switch (IG2) through the 
multi-purpose fuse number 17 in the junction 
block. 

• If the ignition switch is turned to the "ON" posi-

tion, the M-ASTC-ECU turns on the valve relay, 
and monitors the power supply voltage to the 
valve relay at terminal 55.

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ABS DTC SET CONDITIONS
M-ASTC-ECU always monitors the ignition switch 
(IG2). DTC 31 is set when the M-ASTC-ECU detects 
an open circuit for approximately four seconds with 
the ignition switch at the "ON" position.

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TROUBLESHOOTING HINTS

• Damaged wiring harness or connector

• Malfunction of the M-ASTC-ECU

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DIAGNOSIS

Required Special Tools:

•  MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

AC204545 AC

CONNECTORS: B-17, B-18

B-17 (GR)

B-18 (B)

AC204674

AB

B-21X (VALVE RELAY)

CONNECTOR: B-21X

AC204675AB

D-116

CONNECTOR: D-116

AC204547AB

CONNECTORS: D-208, D-212

D-208

D-212

JUNCTION BLOCK
(FRONT VIEW)

AC204548AL

E-111

CONNECTORS: E-108, E-111

E-108

AC203901AD

CONNECTORS: E-119, E-120

E-119

E-120

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-40

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, read the diagnosis 
trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Check the ABS DTC.
Q: Is ABS DTC 52 set?

YES : Carry out the troubleshooting regarding DTC 52. 

Refer to 

P.35B-68

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NO :  Go to Step 2.

STEP 2. Using scan tool MB991958, read the HBB 
diagnosis trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Check the HBB DTC.
Q: Is HBB DTC 16 set?

YES : Carry out the troubleshooting regarding HBB. Refer to 

GROUP 35A, HBB Diagnosis 

P.35A-18

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NO :  Go to Step 3.

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-41

STEP 3. Check the battery.

Refer to GROUP 54A, Battery 

− On-vehicle Service − Battery 

Testing Procedure 

P.54A-6

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Q: Is the battery damaged?

YES : Charge or replace the battery and then go to Step 5.
NO :  Go to Step 4.

STEP 4. Check the charging system.

Refer to GROUP 16, Charging System 

− Diagnosis 

P.16-3

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Q: Is the charging system damaged?

YES : Repair the Charging System and then go to Step 5.
NO :  Replace the M-ASTC-ECU and then go to Step 5.

STEP 5. Recheck for diagnostic trouble code.
Q: Does DTC 16 reset?

YES : Start over at Step 1.
NO :  The procedure is complete.

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-42

DTC 33 : Stoplight Switch System

AC204646AB

Stoplight Switch Circuit

AC204676 AB

DETICATED FUSE No.16

RELAY BOX

AC204677AB

CONNECTORS: D-28, D-29, D-123, D-125

D-28

D-29

D-125

D-123